1. Field of the Invention
This invention relates to a sealing ring for sealing a pin which is axially displaceable mainly in one direction and extends through a passage in a housing wall into a chamber internal to a housing. The pin has a large radial clearance for motion in the passage. A sealing ring housing is inserted into an annular groove in the housing wall to support a ring made from wear-resistant material which is seated on the pin with small radial clearance and with radial clearance of motion in the sealing ring housing, and with a slide ring seated on the pin without clearance and having large radial clearance of motion in the sealing ring housing.
2. Description of the Prior Art
From the German unexamined patent application DT-OS No. 2,154,228, a sealing ring is known for sealing a pin extending through a housing wall, said ring having an annular housing screwed into an annular threaded groove in the housing wall. Radially supporting itself against the circumferential inner face of the annular sealing ring is an outer circumferential face of a ring which is made from elastic material and is biassed against the pin against which it rests with its radial inner face. In order to improve the gliding ability, a slide ring is disposed between the elastic ring and the pin, said slide ring consisting of a plastic material having good antifriction properties. On both sides of the elastic ring, there are disposed supporting rings made from non-deformable material. Said supporting rings, which have large radial clearance of motion in the seal housing, are seated on the pin with but little clearance in order to prevent the elastic ring from being deformed in an axial direction or from being drawn into the slot between the supporting ring and the pin.
The disadvantage of said sealing ring is that particles of dirt and humidity may penetrate with the pin into the interior of the housing from the outside. Further, higher forces have to be applied for displacing the pin because the elastic ring rests against the pin with bias. Moreover, it is a disadvantage that for a radial movement of the pin the elastic ring needs to be deformed which equally requires higher forces.